Abstract
This work aims at utilizing modern computational microstructural modeling tools to accelerate the understanding of phase stability in austenitic steels under extended thermal aging. Using the CALPHAD approach, a thermodynamic database OCTANT (ORNL Computational Thermodynamics for Applied Nuclear Technology), including elements of Fe, C, Cr, Ni, Mn, Mo, Si, and Ti, has been developed with a focus on reliable thermodynamic modeling of precipitate phases in AISI 316 austenitic stainless steels. The thermodynamic database was validated by comparing the calculated results with experimental data from commercial 316 austenitic steels. The developed computational thermodynamics was then coupled with precipitation kinetics simulation to understand the temporal evolution of precipitates in austenitic steels under long-term thermal aging (up to 600,000 h) at a temperature regime from 300 to 900 C. This study discusses the effect of dislocation density and difusion coefficients on the precipitation kinetics at low temperatures, which shed a light on investigating the phase stability and transformation in austenitic steels used in light water reactors.
| Original language | English |
|---|---|
| Pages (from-to) | 282-293 |
| Number of pages | 12 |
| Journal | Journal of Nuclear Materials |
| Volume | 448 |
| Issue number | 1-3 |
| DOIs | |
| State | Published - May 2014 |
Funding
This research was supported by the US Department of Energy (DOE), Office of Nuclear Energy, Nuclear Engineering Enabling Technology (NEET) Reactor Materials, under contract DE-AC05-00OR22725 with UT-Battelle, LLC. Pandat software from CompuTherm LLC is acknowledged. Discussion with Dr. P.J. Maziasz from ORNL, Dr. Ernst Kozeschnik from Vienna University of Technology is also acknowledged.